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 So who is smart enough to tell me what's inside the camblock 
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Post So who is smart enough to tell me what's inside the camblock
I am doing some reverse engineering on my own modular pan/tilt head design. Kessler Fusion uses DC encoder motors and Camblock uses stepper motors, I understand that. But what I am trying to find out is what worm gears or gearboxes they use internally to change the axis of the output shaft?
If they use worm gears I would like to know if they use anti-backlash type (I would assume so?) and what motors they use.

So who out there has some real input on this matter?

Any insight would be much appreciated, and find the pot at the end of the rainbow would be a photo of a open unit, either one would do.

I am holding thumbs on this one. :?:


Wed Jul 04, 2012 1:39 pm
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Post Re: So who is smart enough to tell me what's inside the camb
This might be of interest: http://www.micro-drives.com/kessler-crane.aspx

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Wed Jul 04, 2012 3:15 pm
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Post Re: So who is smart enough to tell me what's inside the camb
Thank you for that bit of insight. I was looking a little deeper though as per my original post. Interested in the gearing of the 90 degree gearing they use, i.e. worm gears.

But I thank you again, I have used motors very similar in my initial slider design. But I am now looking at improving the standard gearmotor with encoder feedback/position control. And to build my own pan/tilt head with the low profile design of the Fusion and Camblock systems.


Thu Jul 05, 2012 12:43 am
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Post Re: So who is smart enough to tell me what's inside the camb
It's very unlikely that they use anti-backlash gears. These typically have issue under torque. I would expect that they use a standard, low-backlash worm gear drive wherein the gearbox has been machined to correct tolerance to mate the gears to the manufacturers spec. But, we're just hypothesizing here. Before they changed their blog, there was a photo that had a bunch of disassembled blocks in the background, which showed what looked like a worm gear housing to me (well, it looked exactly the same as our engineers, myself, and several other people have designed =). As for which worm gears? You're very unlikely to get any detail as to the pitch, manufacturer, etc. out of either =) Just pick the ones that meet your needs, and go from there. The hardest part is getting the tight tolerances at a good price. Neither will have used off-the-shelf boxes, as they are egregiously expensive for low-backlash boxes and would have form-factor problems inside of the enclosures.

If it helps at all, in our current design (in-progress), there were no stock worm gear sets that met our requirements for backlash, reduction, size, and mounting. We are getting custom gears produced, I suspect that pretty much everyone else did similar based on what limited information I have.

!c


Thu Jul 05, 2012 8:27 am
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Post Re: So who is smart enough to tell me what's inside the camb
I have been around Mark Roberts Products for many years he doesn’t use worn gears mainly timing pulleys. Draw you own conclusion . :D


Thu Jul 05, 2012 10:33 am
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Post Re: So who is smart enough to tell me what's inside the camb
DISPLACEMENT 1 wrote:
I have been around Mark Roberts Products for many years he doesn’t use worn gears mainly timing pulleys. Draw you own conclusion . :D


Timing pulleys are great for zero backlash, not so great for gear reduction == MOAR POWAR! Rawr. =)

!c


Thu Jul 05, 2012 10:51 am
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Post Re: So who is smart enough to tell me what's inside the camb
shutterdrone wrote:
DISPLACEMENT 1 wrote:
I have been around Mark Roberts Products for many years he doesn’t use worn gears mainly timing pulleys. Draw you own conclusion . :D


Timing pulleys are great for zero backlash, not so great for gear reduction == MOAR POWAR! Rawr. =)

!c


Ah I am the one that does 6 meter vertical dolly moves. What more power do I need ? ;)


Thu Jul 05, 2012 11:19 am
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Post Re: So who is smart enough to tell me what's inside the camb
6 meters? Bloody hell!

As I understand you use pulleys, do you happen to know how much weight a 10mm timing belt (T5) can support before it snaps? They look pretty solid.


Edward


Thu Jul 05, 2012 12:29 pm
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Post Re: So who is smart enough to tell me what's inside the camb
I seem to remember the Milo uses a ballscrew for the dolly tracking, but don't quote me on that.

Edward


Thu Jul 05, 2012 12:33 pm
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Post Re: So who is smart enough to tell me what's inside the camb
edward wrote:
6 meters? Bloody hell!

As I understand you use pulleys, do you happen to know how much weight a 10mm timing belt (T5) can support before it snaps? They look pretty solid.


Edward


Kevlar fibers or polyester? The HTD 5M @ 10mm w/ Kevlar I have has a breaking strength of 1,960 newtons. I'll leave it up to someone else to convert that to weight. =)

!c


Thu Jul 05, 2012 3:25 pm
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Post Re: So who is smart enough to tell me what's inside the camb
That's about 200 kg. Sounds like a lot of force.


Thu Jul 05, 2012 11:36 pm
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Post Re: So who is smart enough to tell me what's inside the camb
Milo uses a rack and pinion to drive along track which is made up of linear sliders . Track alone must cost a fortune and it takes quite a time to set up. Think the jib arm uses ball screws and not sure what the hell goes on in the pan tilt head . But their again I hope we not building Milos not known for their portability . Things I have come across over the years are probably early versions of the SFH 30 pan tilt head and a couple of model movers which all had timing pulleys . Studio I am in at mo as a old Panther Rig .Big lump of a thing with a Mitchell head on it . Hoping to convert them to a smaller lighter future. :D
Don’t think you would snap a timing belt . The bigger problem is skipping teeth but not insurmountable .
Noticed on the Camblock site since we are on their thread, they use a assister weight for vertical moves. This is either for safety reasons or their isn’t enough torque in the system to lift the pan tilt head and camera . Does this mean their isn’t a worm gear in their as their so powerful ?


Fri Jul 06, 2012 11:54 am
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Post Re: So who is smart enough to tell me what's inside the camb
Thanks for the many responses.

Firstly camblock and Fusion could not use timing belts. How would it be possible to transfer power through 90 degrees in such a shallow form factor? If am working on a design now that uses 140:1 reduction with worm gears, no gearbox on motor (this would only compound the backlash error as there would be an additional drivetrain with backlash). 2500 rpm motor direct to 140:1 calculates to 17.85 rpm at 12V max. I think this would be a good starting point to achieving a simple low backlash system with good torque for a pan/tilt head. I will design the system to be adjustable in regards to the mating between the worm and worm drive gears.

As soon as I have the aluminum on the milling machine I will post a few pics.


Fri Jul 06, 2012 1:41 pm
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Post Re: So who is smart enough to tell me what's inside the camb
I'd be very interested to see what you do, as I messed about with worms and anti backlash wheels and was never quite happy as to the bulk of it all.

Edward


Fri Jul 06, 2012 2:26 pm
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Post My near complete MOCO slider
Here it is, please do not judge the finish of the surfaces. All components will go through a surface finishing process and bead blasting before being hard anodised (black). Rig as shown has many missing bolts as I have been disassembling and reassembling the system many,many times to check fit and tolerances as I go through the machining stages for each component. Every part on the slider is custom machined right down to timing belt pulleys.

As I mentioned before, I am limited to many components that many living in Europe and the US take for granted, hence making the most of the basic local supplies. All aluminum is 6083 T6 grade and all fixtures are stainless steel. Running wheels are industrial grade plastic with ball bearings. Belt ordered from SDP-SI supplies in the USA.
Completely free of slop and backlash.
I have included 3 picture sheets with Fig1 through Fig 12 with some description for each.

Here it goes:
Page 1:
What I wanted to design was a rig that was easy to set up and use with many of the industries grip equipment. So as you can see in (Fig1), I design the legs to be adjustable and can be folded back if I want to lie flat on the floor. At the end of each leg is a Spigot holder which will accommodate anything from spiked feet, suction cups to 19mm length grip rods. If I wanted to screw the feet to the trunk of a tree this would allow this. Endless mounting options.
Fig 2. shows legs folded away and motor mount swung 90 degrees if needed to pack away or if it might get in the way under certain circumstances.
Fig 3. shows end caps removed from tubing, beneath the caps are threaded inserts, these inserts can also be used for grip equipment and spiked feet for vertical mounting etc.
This page also shows motor and mount removed and hand crank installed. Hand crank fits directly onto pulley with ball bearing type snap action.

Page2:

Fig 4. Custom made pulleys and dual ball bearing supports.
Fig 5. Sliding carriage wheels and belt clamps
Fig 6. Friction system and adjustment knob. Before you guys shout 'Kessler', this type of friction control method has been used on thousands of machine designs for the last 150 years.
Fig 7. Slider length currently 1.8 meters travel ( any length tubes can be used)

Page 3:

Fig 8. Carriage plate with mounting holes
Fig 9. Rails centre support for tripods and other grip equipment (also functions as rail support and tolerance adjustment between centers)
Fig 10. Screws for locking cam adjustment for wheel gap
Fig 11. Carriage lock system ( thought this would come in handy if carriage needed to be locked off in position while changing batteries or remounting camera etc.)
Fig 12. Side view of low profile design (my theory is to have as low a CG as possible, this will also be implemented in my pan/tilt head that is now in the machining stages)

I will post some photos soon of the various pant/tilt components being machined, I have put alot of thought into the design and will be building two complete heads. One with DC gearmotors with encoders and the other with Stepper motors for motion control running with Dragonframe 3.0.
The slider has two complete motor systems on mounts which take seconds to change. Again one DC and other a stepper. I intend to have both, a motion control system aswell as a portable timelapse system.


I would appreciate comments and advice, I am always open to suggestions. The pan/tilt head has been a really bunch of design trouble, but I think I have narrowed it down. But design is evolution, often changing ideas as the machining process is underway.

Regards


Attachments:
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Page2.jpg
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Page1.jpg
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Mon Jul 09, 2012 8:52 am
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Post Re: So who is smart enough to tell me what's inside the camb
Very nice you have obviously got a very good machine shop . Are you a cad cam man ? Look forward to seeing the finished rig think theirs going to be a lot of different rigs out their in the near future bet its getting a bit worrying for the pro manufacturers . Did you see Edwards post about Harmonic gear boxes do like the idea of them if a tad expensive :cry:


Mon Jul 09, 2012 10:04 am
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Post Re: So who is smart enough to tell me what's inside the camb
Cad cam man? Not sure what you mean by that terminology, but if I answer your question it would be this. I use a pencil on paper and only manual type machines (no CNC here). I wish I had CNC, it would take me to a new level of refined design.
Did not get the gearbox info you mentioned posted by Edwards.


Mon Jul 09, 2012 10:14 am
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Post Re: So who is smart enough to tell me what's inside the camb
Well even more well done . Yes I meant CNC just makes life a lot easier bizarrely I use Google sketchup for the cad side its free and I use it for other stuff .
The gear boxes must have been in another post some ware but this is their site I think http://www.harmonicdrive.de/english/products/


Mon Jul 09, 2012 10:23 am
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Post Re: So who is smart enough to tell me what's inside the camb
darthmuller,

Nice rig! I'm not sure why you want to build two different pan tilt heads, wouldn't one be enough to do all you want? I can certainly do time lapse and motion control with the same head, although I use software and controller that can do this (Mantis).

After building a pan/tilt head with planetary gears and finding that it had some backlash (I should've known better, but I am learning!) , I also experimented with worm gears with anti backlash wheels, these certainly gave me no backlash, but I must have been doing something wrongly because I put the load on the wheel shaft and it got a bit bumpy on one direction when I put all the camera weight on it. The wheel shaft was supported by two bearings on either side, but I didn't use thrust bearings at that stage. My problem was almost certainly to do with the anti backlash wheel tension....If I had to try again, I would probably use worm and normal (non split)) wheeI and I would try to make a mechanism that would apply pressure on the worm to maintain variable contact with the worm wheel.

In any case, I abandoned the worm gear idea and decided to bite the bullet and go for harmonic drives because of many factors, including zero backlash, ease of designing around them, flat output flange that makes it easy to attach things to it, nice reduction 100:1, silent, beautifully made...and the feeling, albeit in my mind, that I had the rolls royce of gearing.

As for linear sliders, I have the Omnislider. It is very nicely made. However I am building a more complex rig, and the slider will have much wider (dual) tracks based on ball screw and Hiwin linear profiles.

I received the ball screw with anti backlash nut yesterday and it seems not to have any backlash. I went for a 20mm diameter rod, 5mm pitch which I have calculated will give me the speed I want as well as being heavy duty. The 5mm pitch is approximately the equivalent of reducing 25:1 on your slider motor with pulley which I find satisfactory, any more reduction than that and I can't get the speeds necessary for regular video, any less, and things could start to get jerky with a stepper. Needless to say, I haven't made the jig yet to try it out, there is a small, grinding feel when you turn the anti backlash nut by hand, though there is practically no resistance, it's like turning a nut on a bolt. I think the grinding feel will go (it is not greased) and I hope it won't affect the smoothness.

Like Displacement, I also use Sketch up, nice for reference and to visualise your thoughts on a 3-D environment.


Edward


Wed Jul 11, 2012 11:21 am
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Post Re: So who is smart enough to tell me what's inside the camb
Edward

I feel the same way about the anti backlash worm drives. I have decided to make my own design like you mentioned, keeping the worm tensioned against the drive gear in order to eliminate back lash as much as possible. The reason I am building two heads is: I am crap with programming, so I hope to build the Stepper motor pan/tilt head first and get that up and running with Dragonframe and play around with that for a while. Then I can tackle the DC motors with encoder build. I want to create a closed loop circuit system and I have asked for some help of a friend who has played around with robotics in the past. I need this guy to help me create a closed loop system and basic software. Using motors with planetary gearboxes with US EP4 optical encoders and controllers from Phidgets.

It is going to be interesting.
I will use 45X58X7mm deep goove bearings on each axis, keep it nice and stable.


Wed Jul 11, 2012 12:13 pm
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Post Re: So who is smart enough to tell me what's inside the camb
The camblok uses timing belts and either very low worm drive reduction or a helical gear. Most real time moco rigs like the Milo use reductions of 5-1 and larger motors because they operate at faster speeds for real time. I have worked in the VFX business for years. There is always a tradeoff in designing these things that will go very fast. Steppers are used for repeatability and servos are used where you need max speed and quiet drives. For timelapse larger reductions 60-1 up to 120-1 work well because you need smaller increments of motion not speed. I have been using NEMA 17 size motors for time lapse and I built a turntable with a NEMA 34 motor for speed. One thing about the Milo, it's a great system and quick to set up. A lot of thought has been put into making it easy to shoot with on location. I worked a commercial and the milo crew had the rig off the truck and ready to set up the shot in something like 40 minutes. That's wicked fast for Moco. I have done other moco jobs where we spent a day or 2 setting up and programming a 40' dolly move through a model. Just depends on what you are doing.

Check this out, pretty extreme example of high speed moves with Moco
http://youtu.be/qpAN-PVDzDM

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Wed Jul 11, 2012 6:31 pm
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Post Re: So who is smart enough to tell me what's inside the camb
I thought camBLOCK used optically encoded DC motors, not steppers?


Wed Jul 11, 2012 7:16 pm
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Post Re: So who is smart enough to tell me what's inside the camb
darthmuller wrote:
If they use worm gears I would like to know if they use anti-backlash type (I would assume so?) and what motors they use.


Man, I'm working on my time-lapse camera control robot myself, and for weeks I don't sleep, don't eat, only research and document and source components for my project. I'd really like to catch up with you on Skype or something like that to get in touch with you in real-time and share and learn a bit from our experiences and ideas. Whaddya say? You can find me on skype: erosnicolau.

Really really looking forward to hearing from you! ;)


Fri Feb 22, 2013 9:38 am
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Post Re: So who is smart enough to tell me what's inside the camb
Hi Timescapes. I think you are right. The system runs on 12v with a relatively small battery, so dc motors would make sense for minimal power consumption. In fact I think I might have seen somewhere once that they use little Maxon motors. Because most dc servos are usually quite a bit longer than they are wide, this forces a certain orientation inside the case. And given that, the gear drive would have to be a worm. It would be really interesting to see inside one...


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